Foil takeoff block for burglar alarms



Jan. 26, 1960 J. L. cAssELL Fon. TAxEoFF BLOCK FOR BURGLAR ALARMS Filed Feb. 14, 1957 @www United States Patent() 2,922,979 FOIL TAKEOFF BLOCK FOR BURGLR ALARMS Joseph L. Cassell, New York, N.Y., assignor to The Reeve vElectrical Co., Inc., New York, N.Y., a corporation of New York Application February 14, 1957, Serial No. l640,136

2 Claims. (Cl. 339-17) The invention herein disclosed relates to what are known as takeoff constructions for the foil applied to windows in burglar alarm systems.

Considerable diculty has been experienced with the takeoffs now in use because the foil extending from the window glass to the takeoff block is exposed and positioned where it can readily be broken by window washing operations. Particularly, the end of the metal frame of the squeegee brush in normal use by the window cleaner has a tendency to rip and tear away this connection between the foil on the glass and the terminal contact on the takeoff block.

It is the purpose of the present invention to overcome these faults and to provide a takeoff which will fully protect and guard the foil and its connection with the block and to provide this desirable construction in a simple inexpensive readily applied form, which will be small in size but durable and practical in every way.

Other desirable objects attained by the invention and the novel features through which such objects are attained are set forth and will appear in the course of the following specification.

The drawing accompanying and forming part of the specification illustrates certain present commercial embodiments of the invention, but structure may be modified and changed as regards the immediate illustration, all within the true intent and scope of the invention as hereinafter defined and claimed.

Fig. 1 in the drawing is a broken plan view of one of the takeoffs applied and in use on a window frame.

Fig. 2 is a broken part sectional view taken on substantially the plane of line 2-2 of Fig. l.

Fig. 3 is a broken longitudinal sectional view of the block and window frame structure on substantially the plane of line 3 3 of Fig. 1.

Fig. 4 is a transverse sectional view on the plane of line 4-4 of Fig. l.

Fig. 5 is a broken plan view of a double terminal form of the takeoff.

In Fig. 1, the frame of what may be considered a conventional form lof window is indicated at 7, carrying a pane of glass 8, sealed in place by putty 9.

The lead foil which is applied to the glass is indicated at 10.

At the takeoff point, the foil or an insulated extension 11, of the same is closely fitted to and run up over the putty to the face of the frame as shown in Fig. 4.

The takeoff block comprises in the present instance, a small elongated bar or block 12 of insulating material having a shallow transverse groove 13 across the bottom of the same and a narrow passage 14 slightly larger than the tape extending from this bottom groove up to the top of the block.

A terminal plate 15 covers the upper end of passage 14 and is secured in place by screws 16, one `or both of which may be utilized `as binding screws for the takeoff wiring 17, Fig. 1.

Fig. 4 shows how the covered foil or tape, where it substantially Patented Jan. 26, 1960 passes over the face of the window frame into the cross groove 13, is clamped in place and to assure firm hold ing, the surface of this cross groove may be roughened or embossed as indicated at 18. The present practice is to emboss the name of the manufacturer and the identifying part number at opposite sides of the lower entrance to the upright channel 14 as shown in Fig. 4, such embossment serving the double purpose of identification and for providing a strain relief securely holding the foil to the frame structure.

Fig. 4 shows embossments 18, located in the cross channel or groove 13, at opposite sides of the upright passage 14, so as to bind against the insulated extension 11, of the tape at whichever side the extension may be brought into the groove or if the extension be doubled to increase the thickness of material for the clamping action before extending the end of the extension up through passage 14 to the terminal plate. For practical reasons, the embossments at one side of the vertical passage may be the name of the manufacturer and the embossment at the Aopposite side of the passage the identifying part number. Whichever is used, or if both embossments are used, they form a desirable strain relief for securely holding the tape extension firmly in place on the window frame.

At the terminal end, the insulation is removed from the foil extension andthe uninsulated portion turned over the face of the block as indicated at 19, where it is secured and electrically connected by the overlying terminal plate 15.

In the manner described, the terminal portion of the foil is to a large extent covered and protected but further protection is afforded inthe invention by a guard member 20, projecting from the side of the block over that part of the foil extending from the glass up beneath the block.

As will 'be clear from Figs. l and 4, this guard lug projects from the side of the block far enough to ward ol any engagement of the squeegee or other window washing element with the extended portion of the foil.

Fig. 1 shows how this outstanding guard lug may be rounded top and bottom, so as to defiect a squeegee brush or the like away from the takeoff in movement either up or down or laterally over the window surface.

The takeoff block may be secured on the window strncture by screws 21, and these same screws as shown in Fig. 3 serve to apply the clamping pressure to the section of the foil extended across the bottom of the block.

To assure firm anchorage, screw seat inserts 22 may Ybe provided in the block for the contact screws 16.

Where it is desired to take both terminal wires off the same block, the block may be made approximately double the length as shown in Fig. 5, with one set of the terminal elements described at each end of the block.

Also in such case, it is usual to provide a grounding screw seat insert 23 on the block between the terminals for the binding screw of a ground wire.

The takeoffs are easily applied and occupy small space, so they may be used where there would not be room for other such devices. Also they are neat in appearance and do not detract from ornamental surroundings. They cover and protect the terminal ends of the foil and guard against injury from window cleaning or other such operations.

The circuit of which foil 10 forms a part is conventional and well known in burglar alarm systems. The foil forms a part of this circuit. It is a fragile metallic tape or strip which will break and interrupt the circuit if the glass is broken and which, on the other hand, is capable of carrying the alarm circuit current.

Fig. 5 shows how the foil on the glass may be connected in the circuit. The takeoff terminal 15 at the left in this view is connected with one end of the foil 10 and this foil after being extended around the glass is brought to the takeoi terminal plate 15 at the right in this view. Wires connected with the two terminal plates 15 extend the circuit through the alarm equipment. While there are yno oitale cireuit wires shown in this particular view, Fig. l shows how-such a wire 1Y7'may be iconnected-vvith'the terminal plate by means of one of the plate securing screws ,16.

1. A takeo ,block for the foil .which is applied to a window in a burglar alarmvsysterrr, comprising aY small block 4of insulating material adapted :to be mounted on a window frame in position adjoining the glass :in the frame, said block having a shallow groove across the bottom of the same providing a restricted passage for an insulated end portion of foil extending from `foil'on the glass up'over the edge ,of the fran-Are, screws extending down through the top` of the .block `at ,opposite'sides' of said groove for lfastening the block'v on lthe frame and for clamping theportion ,of insulated foil in the groove against the face of ,the frame, said block having an opening extending from the groove in the hottorn'of the block up through the top ,of the bleek for passage of *a continuing portion .of the` foil extending from said kcross groove up through the top of the block, `a terminal lplate overlying the fop 0f the blck and slitentlagaqrss the upper ,end of said opening for contact-making clamping engagement with an uninsulated end portion `of the foil extending up through said opening and lbent over the top of the `block and,` screws at Opposite sides of said opening for securing said terminal plate down in clamping engagement over said uninsulated end portion of the foil.

2. The invention according to claim 1 with a lateral with said transverse groove in the bottomrof the block and thereby positioned to cover said end portionrof the foil extending from the glass to the groove in the bottom of the block to Ward oj Yand prevent Window cleaning implements destructively engaging said end portion of -the foil. 

